Pharmacokinetics of fluorocarbon aerosol propellants such as fluorocarbon 11, 12 and 114 are studied in dogs. Their disposition half lives, volume of distribution and pulmonary clearance were estimated. The possible accumulation is studied. An ultra-sensitive head-space method is developed to assay propellants in blood and other biological fluids and tissues. Binding interactions with human and bovine albumin and globulin are investigated. Solubilities of fluorocarbon 11 in various dog tissue homogenates are studied. Correlation between blood or tissue levels and toxic effect are being studied. Interspecies difference in solubilities of propellants in blood and plasma are found. Bibliographic references: W.L. Chiou and J.H. Hsiao: Thermodynamic aspect of the interaction of dichlorotetrafluoroethane with bovine albumin. Pharmacology. 13:128-136 (1975); S. Niazi and W.L. Chiou: Fluorocarbon aerosol propellants IV: Pharmacokinetics of trichloromonofluoromethane following single and multiple dosing in dogs. J. Pharm. Sci. 64:763-769 (1975).